With an evolution of mobile communications from the third generation (3G) communication to the fifth generation (5G) communication, mobile communications need to support transmission of large-volume data and connection of masses of user terminals.
When data is transmitted between a base station and a user terminal, the data needs to be modulated to a frequency band and then transmitted over the frequency band. However, the frequency band is limited and non-renewable. However, during data transmission in the prior art, a transmission channel needs to be established between the base station and the user terminal. The transmission channel occupies the entire frequency band. Before the transmission channel is released, that is, when no data is transmitted over the transmission channel, the entire frequency band may not be used by a third party.